1. Field of the Invention
This invention relates generally to hand trucks and more particularly to a braking system for hand trucks.
2. Description of the Prior Art
Various arrangements have been devised for preventing hand trucks from rolling while unattended. Early examples of U.S. patents disclosing arrangements with levers and links and rods are found in U.S. Pat. Nos. 1,496,548 to Knight, 1,520,941 to Funk, 1,559,796 to Shuey et al., and 2,389,320 to Nance. An early patent showing an arrangement with pulleys and cable is the U.S. Pat. No. 2,169,781 to Abresch. In more recent years, numerous patents have been issued for braking systems which lock caster wheels to prevent them from rolling or from swiveling or both. An example is U.S. Pat. No. 4,793,445 to Collignon et al. Another is U.S. Pat. No. 4,248,445 to Vasser. All of the aforementioned patents have some means whereby a single control can put the brakes on more than one wheel. There are also arrangements where individual casters can be locked by a lever on the caster itself. An example is the U.S. Pat. No. 3,388,419 to Crawford. No doubt there are other arrangements for locking casters individually and for locking them as a group and of which we are unaware. There has remained a need for a simple, reliable, inexpensive, durable and easily operated system for locking wheels of an otherwise conventional hand truck. The present invention addresses that need.